Joint



June 7, 1938. H (g,l BLEVlNS JOINT Filed Aug. 17, 1937 2 sheets-sheet` 2 j WITNESSES: INVENTOR. m BY @uml (UCQAmf r ATTORNEYS.

Patented June 7, 1938 PATENT QFFICEl JOINT Herman G. Blevins, Sewckley, Pa., assignor to The National Supply Company, Pittsburgh, Pa., a corporation of Pennsylvania Application August 17, 1937, Serial N'o. 159,484

3 Claims.

This invention relates to oil well casing, joints for connecting the casing end to end in a well and to improved methods for making joints, and more particularly is concerned with welding casing end to end and with butt joints.

Heretofore it has been the standard practice to line drilled well holes, and particularly deep holes as made in drilling for oil, with pipe or casing which has been connected end to end usually by 4threaded joints Sometimes the joints are made by threading each end of the casing with a male thread and then employing a female coupling sleeve. Again the ends of the casing have been upset and formed with complementary male and female joints. Threaded joints, regardless of the type, are relatively expensive to manufacture and although they can be conveniently made up or taken apart in the field, they are by their inherent nature of greater over-all diameter than the body of the casing proper so that in order to finish the well with a desired casing size it is necessary tostart drilling and casing the well at a considerably larger size to allow the various strings of casing forming the complete casing program to be nested or positioned one inside the other. The larger the starting hole size is, the greater is the cost oi drilling the well with a particular finishing hole size'since a greater amount of earth has to be removed and a greater tonnage of casing must be employed.

It has been proposed heretofore to reduce the costs of casing an oil well by welding the lengths of casing end to end and thereby eliminate the threading operation. One manner of welding casing end to end which has been employed is to form one end of each casing length with a bell which is adaptedto receive a spigot end on the other end of another length of casing. The end of the bell is then welded to the side wall of the end of the spigot to provide what might be termed a filet weld joint between the casing lengths. While this saves the cost of threading, the overall diameter of the joint is not materially reduced so that the advantage of having the smallest possible starting hole size for a given finishing hole size is not obtained. It has likewise been proposed to butt weld casing lengths end to end but so far as I am aware, this has not met with entire success due, I believe, chiey to the dimculty of butt welding the casing lengths end to end when in a vertical position and because the joints are subjected to high stresses in use which necessitates a weld approaching the strength of the parent metal.

It is the general object of my invention to avoid and overcome the foregoing and other difliculties of and objections to known joints for oil well casing and methods of making the joints by the provision of an improved b utt Welded joint and a method for making the joint whereby the weld 5,

can be rapidly and uniformly performed with the casing lengths in the vertical position and substantially of a strength and other physical characteristics desired.

Another object of my invention is the provision 10 of an improved casing length particularly constructed and arranged to facilitate joining it end v to end with another casing length in a well with a welded butt joint.

Another object of my invention is the provision 15 of ca sing, joints therefor and methods of making the jointswhereby an oil well can be cased to provide a desired iinishing size and wherein the starting size of the well is retained at a minimum in that the exterior and interior diameters of the joints of the casing are substantially the` same as the body of the casing and wherein the joints may be rapidly and efficiently formed by `an ordinary welding operation.

The foregoing and other objects of my inven- 25 tion are achieved by the provision o'f a length of oil well casing comprising a body portion of uniform weight per foot and having a uniform internal and external diameter from end to end. One end of the casing is preferably formed with 3g, a substantially ilat land of desired radial width substantially perpendicular to the casing axis and at the radially inner portion of the casing, IThe radially outer portion of the casing end is cut away to provide clearance and a complementary 3;, part of a welding groove. The other end of thev casing is preferably formed with a substantially flat land, substantially perpendicular to the cas-J ing axis and of, substantially the same extent and radial position as the first-,named land. The re- 40 mainder of said other end of the casing is formedA with a, groove usually of substantially semi-circular cross-section to provide a complementary part of a welding groove and having a radially outer portion extending axially toward the end of 45 the caslngbeyond certain radially inner portions of the groove.

In accordance with the method of my invention for butt welding lengths of oil well casing down a hole, one end of a casing length is formed with a pocket for receiving and retaining fluid welding metal when the casing is in a vertical position. The end of another length of casing is formed with a cut-away portion which, together with the pocket of the first-named casing, provides a weld-` ing groove between the ends of the casing to be joined together. The first-named casing length is placed in the hole with the pocket uppermost, and the other casing end with the cut-away portion is brought into substantially abutting relation with the first casing so that the pocket and cut-away portion form the welding groove which is then filled with welding metal usually from an electric varc electrode.

/A welded butt joint between two lengths of oil well casing as comprising my invention includes a pocket in the upper end of the lower casing length andv a cut-away portion on the lower end of the upper casing length, which pocket and portion together dene a welding groove between the casing ends, and welding metal filling the` groove and welded to the casings.

For a better understanding of my invention reference should be had to the accompanying drawings illustrating one embodiment of my invention and wherein Fig. 1 is a vertical crosssectional view of a casing program constructed in accordance with my invention; Fig. 2 is an enlarged side elevation of a joint embodying my new principles with certain portions of the joint being broken away to illustrate parts thereof in cross-section; Fig. 3 is an enlarged fragmentary vertical cross-sectional view of the joint illustrated in Fig. 2; and Fig. 4 is a view similar to Fig. 3 but of a modification of -my invention in.

which the ends of the casing relation.

Referring particularly .to the drawings, the numeral l indicates generally an oil well casing program including an inner bottoming or finishing string l2 of individual casing lengths connected end tol end by butt joints and extending are not in abutting from the top of the well to the bottom thereof.

The numeral I4 indicates an intermediate string of casing extending around the outside of the bottorning string /I2 and functioning to seal ofi heavy shale, water or other substances, as is wellr understood by those skilled in the art. This string, like string I2, is comprised of a plurality of lengths of casing which are connected end to end by butt welded joints. Surrounding the intermediate string I4 is the outside or surfacing string I6 of casing likewise consisting of a plurality of separate lengths connected end to end by vbutt welded joints with the string serving to seal off surface water or the like.

-It will be seen that in running an oil Well thousands of feet into the ground in order to finish with-casing having an internal diameter ,facilitates the rapid production of uniformly strong and leak-proof welds of the butt typev for connecting casing end to end. IV have discovered that welding casing end to end is greatly facilitated by making the upper end of the casing when positioned in the well with a pocket or other means for receiving and retaining uid welding metal, and by forming the lower end of the next casing length to be added with a lcut-away por-- tion to provide clearance to the pocket. Specifically, as shownv in Fig. 2, the lower end/of the upper casing length marked U is formed with a cut-away portion while the upper end of the lower casing length marked L is formed with a pocket 22 which, together with the cut-away portion 20, provides a welding groovebetween the casing ends which is adapted to receive and retain the welding metal. The pocket 22 holds the fluid welding metal against vdisplacement out of the Welding groove while the cut-away portion 20 allows the end of the welding rod to be` directed substantially into the pocket 22.A

As perhaps best illustrated in.- Fig. 3, each end of the casing is preferably formed with a substantially flatland or surface marked 24 which is substantially perpendicular to the axis of the casing, and which are complementalto and opposed to each other so that in aligning the casing lengths with each other the lands 24 may be engaged. The radial width of the lands 24 can be made as desired. I specifically contemplate decreasing the radial width of the land almost to nothing as long as the end of the casing is square, i. e., perpendicular to the casing axis.

Likewise the radial width of the land can be incentering or concentricity of the casing ends preparatory to welding.

. As shown in Fig. 3, vthe casing ends may be welded together with the lands 24 engaged. However, I have found that it is often advantageous to form the welded joint with the lands 24 being slightly spaced apart from each other, as seen in Fig. 4, so that the metal forming the weld is free to contract or shrink as it\cools after welding. When the area of the lands 24 is small they may y be engaged during welding as any shrinkage of the weld on cooling can be absorbed by the thin lands without adversely stressing the weld. The

manner of making the Weld illustrated in Fig. 4'

can best be accomplished with the aid of an electric arc Welder in which the current is vgrounded to the casing lengths and the direction of current flow is such thatthe metal from the electrode is deposited in the pocket 22 and the cut-away portion 20 without tending to fly be# tween the lands 24 and into the interior of the joint.

It should be understood that I contemplate forming the pocket 22 of lany particular cross- `section so long as its function as a pocket is not destroyed. In other words, the radially outer portion of the pocket is nearer the end of the casing than'certain radially inner portions of the pocket and the entire pocket is below the land 24.

rectangular or otherwise. With'respect to the cut-away portion 20, this likewise may be formed in various ways as long as its function is retained, i. e., to permit the ready access to the pocket 22. Instead of beingmade with a.

bevel, as illustrated, it could be formed' as a concave or even convex surface if desired.

The pocket instead of being semi-circular in l `section as illustrated, can be semi-polygonal,

It is believed that the practice of. my method will be understood from the`foregoing description. However, briefly describing the method, a length of casing formed at one end with a cut-away portion and at its other end with a pocket 22 is placed in a well with the pocket 22 uppermost. Another length of casing is positioned in vertical alignment with the first length and has its cutaway portion 20 lowermost so as to form, together with the pocket 22, a welding groove. The welding groove thus provided is readily lled with fluid welding metal even though the casing lengths are in a vertical position and for this work I preferably yuse an electric arc wherein the electrode'is of the'coated rod type which deposits the welding metal directly in the welding groove. Welding clamps or jigs are usually employed to facilitate the operation and when this is done the casing lengths are iirst tack welded together at several circumferentially spaced points, the clamp is then removed and the weld completed. In this manner any number of additional lengths of casing can be added to the string and the casing lowered into the well.

From -the foregoing, it will be recognized that the objects of my invention have been achieved by the provision of an improved oil well casing, casing joint and method of making the joint. The joint has a maximum internal diameter and a minimum external diameter and can be readily made by the ordinary Welder without special' equipment to provide a leak-proof joint. The joint can be made as strong as desired by changing the area of the lands 24, as, for example, from as low as 25 per cent to as high, as 100 per cent of the strength of the casing body proper.

In accordance with the patent statutes I have specically illustrated and described one embodiment of my invention. However, it should be understood that my invention is not limited thereto or thereby but is dened in the appended claims. l v

I clai'm:

1. A welded butt joint for well casing or the like comprising two lengths of casing standing substantially vertically and substantially in end to end engagement, a complementary groove formed on the end of, each casing length and together providing a `welding groove', the groove on the lower casing end -being shaped to retain fluid weld metal therein, the groove on the upper casing end being formed with clearance to permit the entrance of a welding rod or electrode into the welding groove formed between the ends of the casing lengths, and metal welded in the welding groove and securing the lengths of casing together.

2. A welded butt joint for well casing comprising two lengths of casing standing substantially vertically in a hole and having substantially radial portions in substantially end to end engagement, a complementary groove formed on the end 0i each casing length and together providing a Welding groove, the groove on the lower casing end being shaped to retain fluid weld metal therein and having a radially outer portion extending- Aaxially above certain radially inner portions of the groove, the groove on the upper casing end being formed with clearance to permit the entrance of, a welding rod or electrode into the welding groove formed between the ends of the casing lengths, and metal welded in the welding' groove and securing the lengths of casing together. l

3. A length of oil well casing comprising a body portion of substantially uniform weight per foot and having substantially uniform internal and external diameters from end to end, one end of the casing being formed with a substantially at land substantially perpendicular to the casing axis and at the radially inner portion of the casing and with the radially outerportion of the end cut away to provide clearance and a complementary part of a welding groove, the other end of the casing being formed witha substantially flat land substantially perpendicular to the casing axis and of substantially the same extent and radial position as the first-named land, the re' mainder of said other end of the casing being provided with a groove forming a complementary 

